PSYC 217 Study Guide - Midterm Guide: Inter-Rater Reliability, Repeated Measures Design, Concurrent Validity

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12 May 2015
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Confounding variable=variable that varies along with independent variable cannot determine which of the variables is responsible for the observed effect. *good experimental design- eliminating possible confounds and that results in alternative explanations. Internal validity= when results can confidently be attributed to effect of iv. External validity= extend to which findings may be generalized. Posttest-only design: obtain 2 equivalent groups of participants, intro the iv, measure effect of iv on dv. Makes it possible to ascertain that the groups were, in fact equivalent at the beginning of exp. Usually not necessary if participants have been randomly assigned: min 20-30 per condition to make random assignment effective. Disadvantages: time-consuming, awkward to administer, *sensitize participants figure out your hypothesis. Can be disguised: can use solomon four-group design. Combo of both posttest-only and pretest-posttest design. Assigning participants to experimental conditions: independent groups design, *diff participants assigned to each of conditions using random assignment.